Paclitaxel is an important active pharmaceutical Ingredient for chemotherapeutic treatment of metastatic cancers. The antitumor activity of paclitaxel is attributed to its interfering mitosis effect. Paclitaxel has been approved by the Federal Drug Agency in the U.S.A. and the Health Protection Branch of Health Canada for the treatment of ovarian cancers. The results of ongoing clinical trials for treatments on other cancers such as breast, lung and colon cancers are also promising.
Paclitaxel is a natural product originally isolated from the bark of the Pacific Yew tree (Taxus brevifolia), and it is also found in bark, needles, and twigs of many other Taxus species including Taxus canadensis. The concentration of paclitaxel in various plant materials is very low, less than 0.1%, which makes the process of isolating the compound from its natural sources very complex and challenging.